This Site is under editing. Site will be open on 25,Dec 2009
GeoPo is developed by Creco Inc in Japan in 2009. It is designed for Twitter usage. Coding method is not so unique, but GeoPo include http://geopo.at/ as a code. This makes GeoPo code linkable. Creco declare Free License for GeoPo code.
It assumes that whole world is square area in Mercator projection.
Divide it into 8x8=6 hierarchically until required precision.
Use [0-9,A-Z,-_] to express which part of 64 areas. Even one character can means location (or area).